You really didn’t give enough information but here’s my opinion on your questions.
How easy is it to use Mapper/Survey to process images and then share the data with clients in Cloud?
Pix4D is easy to use on a basic level. It is streamlined to allow for processing with the default options and having good results.
Sharing on Cloud is also easy and their Cloud is comparable to Drone Deploy, but I still think Drone Deploy’s cloud sharing is batter.
I understand I’ll need to buy Survey and Mapper, but what are the advantages of using a paid version of Cloud in sharing generated data, if any?
Make sure you need Survey and Mapper. Matic is the version that is currently being provided with updates and mapper seems to be on its way out. Mapper does allow things though that Matic does not such as radiometric thermal processing and vegetation indices. Survey is good for vectorization, TIN creation, thinning of point clouds and some other tasks that it makes easier than somthing like ESRI Arc Pro.
If I use the free version, what are the constraints?
Free version of what? Free version of Mapper, Matic or Survey will not allow you to export anything and also will not allow certain processing steps. Free version of the Cloud? Any cloud storage gained during trial versions will expire.
We fly the DJI M30T, I am hoping that its thermal camera is compatible with Mapper. I read that some conversion tool may be necessary.
The M30T will not provide a high quality survey orthomosaic. It can provide maps as any camera can, but they will not be survey grade and will lack detail, coloring and precision accuracy when compared to a dedicated mapping drone such as the Mavic 3 Enterprise (With RTK hat), Matrice 300/350 RTK with P1 camera or even the Phantom 4 RTK.
You would further need to receive corrections with the above systems to achieve survey grade and your M30T receiving corrections would still not be survey grade as it is not a mapping solution for survey grade outputs.
Your thermal camera is compatible with mapper in an RGB visual only way. The maps you can make will be visual only, they will not contain the radiometric temperature values like the older XT and XT2 Flir based sensors had. You could use a free convertor to convert the DJI spec thermal jpegs to TIFF format, then process in mapper and then have a radiometric output.
While the M30T is a great platform, it is not a survey grade mapping drone. It also needs a convertor for its thermal images to follow a radiometric workflow.